Stoppers



A. G. WOOD "Oct; 9, 1962 STOPPERS Filed April 21, 1958 S rm m m m6 r yM A United States Patent 3,057,502 STOPPERS Arthur George Wood, Farnham, England, assignor to Permuta Closures Limited, London, England, a company ofGreat Britain Filed Apr. 21, 1958, Ser. No. 729,601 Claims priority, application Great Britain Apr. 24, 1957 5 Claims. (Cl. 215-47) The present invention relates to stoppers for glass bottles, jars and the like, which are moulded of a resilient plastic material such as polythene, polyvinyl chloride or nylon, and particularly to plastic stoppers comprising a substantially cylindrical body having a plurality of annular ribs therearound which, when the stopper body is pushed into the neck of the bottle or the like, seal against the internal surface of the neck. In known stoppers, the body is generally in the form of a thin-walled hollow cylindrical shell which is closed at at least one end, two or more annular ribs extending around the external periphery of the shell. The stopper may be provided with a head which may be moulded integrally with the body or may be a separate component secured to the body.

By reason of the wide tolerances necessary in the manufacture of glass bottles and the like the internal diameters of the neck portions of the bottles or the like into which the stoppers have to be fitted can vary over wide limits and it has been found that moulded plastic stoppers, of which the dimensions are maintained within narrow limits by reason of the moulding process by which they are produced, are liable to be insecurely held within the necks of some bottles which they are designed to fit, and to slide or pop out due to pressure created within the bottle, for example, by the insertion of the stopper or by variation of the ambient temperature.

Further, the withdrawal of a stopper with annular ribs tends to occur in a series of irregular snatches as each rib moves out of the neck. Due to this irregular action, there is a tendency for the contents of the bottle to be spilled upon withdrawing the stopper, especially with the smaller sizes of bottles.

An object of the present invention is to reduce or eliminate the above difiiculties by forming at least part of some of the contact surfaces of the stopper body (that is the surfaces of the body which contact the internal surface of the bottle neck) with a matte or roughened finish, thereby increasing the coefficient of friction between the stopper body and the internal surface of the glass neck and reducing the wall pressure which would otherwise be necessary to prevent the stopper from being forced out of the bottle.

Another object of the invention is to provide a stopper which is moulded of a resilient plastic material with annular ribs around its external periphery and which can be removed from a bottle and inserted therein with a substantially smooth action.

According to a feature of the invention the matte finish is produced on the selected areas of the contact surfaces by appropriately roughening the corresponding areas of the mould cavity within which the stopper is manufactured. The toughening of the mould surface may be effected by sandblasting or in any other convenient manner.

For convenience of manufacturing the moulding die the Whole of the surface of the cavity which defines the body portion and the ribs may be sandblasted so that the entire body and the reinforcing ribs of the moulded stopper will have a matte finish.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawing in which:

FIGURE 1 is a perspective view of one embodiment of a stopper according to the invention.

FIGURE 2 is an axial section of the stopper of FIG- URE 1.

FIGURE 3 is a perspective view of another embodiment of a stopper according to this invention.

FIGURE 4 is an axial section of the stopper of FIG- URE 3.

FIGURE 5 is a perspective view of a modification.

As shown in FIGURES l and 2 the stopper comprises a body portion consisting of a thin-walled substantially cylindrical hollow shell 1 moulded of Alkathene brand polythene integrally with a head portion 2 which closes the upper end of the hollow shell. Moulded integrally around the outer surface of the shell are annular reinforcing ribs, two ribs 3 and 4 being shown in the embodiment illustrated. The ribs prevent the thin walls of the body from creasing longitudinally when the stopper is forced into a bottle neck, and their outer peripheral surfaces constitute the contact surfaces which engage the internal surface of the neck of the glass bottle into which the stopper is inserted.

The peripheral surfaces of the annular ribs are provided with a matte finish. This is preferably achieved by roughening the corresponding surfaces of the mould cavity in which the stopper i moulded, for instance by sandblasting. I have found that sandblasting with a grit size of 40 to (i.e. grit which will pass through a mesh of 40 per inch but not through a mesh of 100* per inch), and preferably a grit size of 60 to 80, produces adequate toughening of the mould to produce a satisfactory matte surface on the contact sufaces of the stopper.

The lower rib 3 is positioned close to the bottom open end of the sto per body. It prevents the liquid contents of the bottle from seeping into the space between the two ribs. The upper rib 4 is, according to a feature of the invention, made wider than the rib 3 and extends so that its upper edge is approximately level with the underside of the head 2. This wide upper rib enables the stopper to be inserted and removed from a bottle with a smooth action.

The matte finish on the contact surfaces of the ribs increases the coefiicient of friction between the stopper and the internal surface of the bottle neck, so that the stopper is less liable to rise or pop out of the bottle neck into which it is inserted.

The portion of the stopper body extending from the lower rib 3 to the bottom end thereof may be tapered as shown to facilitate insertion of the stopper into a bottle neck.

If desired, more than two annular n'bs may be provided around the stopper body. All of the ribs may be of the same external diameter or, alternatively, one or more of the ribs may be of larger diameter than the others. For example, the ribs may be of gradually increasing diameter from the upper rib to the lower rib, or vice-versa or one or more of the intermediate ribs may be of the largest diameter. In constructions in which the hollow body has a slight internal taper increasing towards the open end thereof (which constructions facilitate the withdrawal of the core of the moulding die), the diameters of the ribs may increase in such manner that the combined radial thickness of the ribs and the underlying part of the hollow shell is constant for all the ribs.

The stopper shown in FIGURES 3 and 4 is similar to that shown in FIGURES 1 and 2 and comprises a body portion consisting of a thin-walled substantially cylin- 3 drical hollow shell 1 moulded integrally with a head portion 2 and two annular ribs 3 and 4.

Additionally there is moulded between the two ribs 3, 4 a plurality of longitudinally extending ribs 5 of approximately of the same height as the ribs 3 and 4. Upon withdrawal or insertion of the stopper, these ribs 5 provide gliding support against the internal surface of the bottle neck and thus ensure a smooth gliding movement of the stopper within the neck. Preferably an even number of longitudinal ribs 5 are provided, arranged in diametrically opposite positions around the stopper body, so as to provide support at diametrically opposed points of the body. If, however, a sufiiciently large number (for example eight or more) of longitudinal ribs 5 are provided around the stopper so as to provide substantially uniform support therearound, the desirability of arranging pairs of longitudinal ribs diametrically opposite to one another does not assume so much importance in achieving a smooth sliding action.

FIGURE 5 shows a perspective view of a modification in which the lower annular rib 3a is wider than the rib 3 in FIGURES 3 and 4.

Some or all of the contact surfaces of the annular or gliding ribs which are adapted to contact the internal surface of the neck of the bottle may be provided with a matte or roughened finish in order to increase the coefficient of friction between the stopper and the internal surface of the bottle neck.

Whilst particular embodiments have been described, it will be understood that various modifications may be made without departing from the scope of the invention. For example, instead of forming the matte surface by roughening the surface of the mould cavity, the stoppers may be moulded with a smooth or polished surface and the contact surfaces, or parts thereof, may be subsequently rendered matte by a separate operation.

Also, the gliding ribs need not be disposed parallel to the longitudinal axis of the stopper body. They can be inclined or disposed helically thereto in which case two sets of oppositely inclined ribs are preferably provided in order to ensure the maximum smoothness of action. In this case the crossing inclined gliding ribs would produce a kind of diamond pattern around the space between the two annular ribs 3 and 4.

More than two annular ribs may be provided in which case gliding ribs are preferably provided between each pair of annular ribs. In constructions in which the gliding ribs criss-cross one another in a manner which blocks any 4 longitudinal passage along the external surface of the stopper body through which liquid might leak, either one or both of the annular ribs 3 or 4 may be eliminated.

In another embodiment, the annular ribs may be made of wavy or zig-zag configuration which are so disposed that oppositely directed crests of two adjacent annular ribs lie in the same plane or overlap in the axial direction. With such constructions the annular ribs themselves also provide the longitudinal gliding ribs and separate gliding ribs may be eliminated.

I claim:

1. A stopper for bottles and the like which is moulded of a resilient plastic material and comprises a substantially cylindrical hollow stopper body which is closed at at least one end, a plurality of annular ribs moulded around the external periphery of the body, and a plurality of rib portions on the external surface of the body and bridging the space between two adjacent annular ribs, the said rib portions being of substantially the same height as the annular ribs. 1 t

2. A stopper as claimed in claim 1, wherein the surfaces of at least some of said annular ribs and rib portions are provided with a matte finish.

3. A stopper as claimed in claim 1, wherein an even number of rib portions are provided and arranged in diametrically opposite positions around the stopper body.

4. A stopper as claimed in claim 1, wherein said rib portions are of slightly less height than the annular ribs.

5. A stopper as claimed in claim 1, wherein the body had a head, the upper annular rib nearest to the head being wider than its height and extending so that its upper edge is approximately level with the underside of the head.

References Cited in the file of this patent UNITED STATES PATENTS 369,784 Furman Sept. 13, 1887 741,169 Sachse Oct. 13, 1903 953,124 Conradson Mar. 29, 1910 1,327,519 Bitler Jan. 6, 1920 2,758,737 Hennings Aug. 14, 1956 2,820,564 Solomon Jan. 21, 1958 2,873,038 Schnier et a1. Feb. 10, 1959 FOREIGN PATENTS 1,067,061 France Jan. 27, 1954 1,160,272 France Feb. 24, 1958 531,207 Belgium Sept. 15, 1954 

